Intel ties upcoming PC-on-a-chip to Rambus

TAIPEI, Taiwan  Intel Corp. will take a crack at putting a PC-on-a-chip late next year. The so-called Timna processor, manufactured with 0.18-micron technology, includes a Pentium II-class processor, a graphics controller, 128 kbytes of L2 cache and  the item that's raising the most eyebrows  a Direct Rambus memory controller.

If Intel follows through with its plan, Timna could drive Rambus DRAMs into the mainstream and stake out a new territory in the low-cost PC space. But motherboard makers here, already struggling to integrate Direct Rambus into high-end Pentium III designs this year, are worried about the hurdles involved in bringing the new memories into volume, low-end systems.

At the same time, Timna is reigniting concerns about Intel's extending its prowess beyond CPUs to stake claims in graphics and memories.

With Timna, Intel is signaling that it is rethinking the pieces of the PC architecture. The processor includes what has typically been referred to as the north-bridge functions of a PC core-logic chip set. As for the south-bridge components, "Intel is now talking about an I/O hub when they talk about core logic, [because] for Timna CPUs, all the core logic does is control I/O devices, mass-storage devices and so on," said one motherboard R&D engineer here. (The engineer, like many other sources here, requested anonymity in light of the fact that the Timna product has not yet been formally announced. Intel declined to comment for this report.)

"First, they control the CPU market. [Next,] the Timna is basically a PC-on-a-chip," said the marketing manager for another Taiwanese motherboard maker. "Now, they want control of the memory market as well."

Some of Taiwan's motherboard makers think this increased integration will not succeed in the market. "For specific OEM applications, the Timna may be a good solution," said another R&D engineer. "Historically though, the market has not had wide acceptance of a set graphics function. Many consumers want the ability to upgrade their video cards."

Indeed, Intel has a troubled history with integrated parts. Its efforts to build in the 1980s all-in-one processors for the notebook market was eventually abandoned, in part because the integrated chips failed to keep up with rapidly changing features demanded by OEMs.

"I think the Timna is an awesomely bad idea," said Peter Glaskowsky, senior graphics analyst with MicroDesign Resources (Sebastopol, Calif.). Integrating so many functions, even at the 0.18-micron level, will mean large die size and high manufacturing costs, he said, but aiming the part at the low-cost market means low margins.

More important, the rapidly shifting graphics market demands frequent updates, but it would be prohibitively expensive to revise Timna because of the MPU component. "What you end up with is a part that is too big, and is lacking in competitive features in both the graphics accelerator and the processor cores, and those are all bad things," said Glaskowsky. The only place such a device might succeed, he said, is the very lowest end of the PC market. Even with a mediocre graphics core, the performance gained by shrinking line widths could make Timna competitive with other low-end parts.

PC makers here also said they fear the problems they are having with Rambus on this year's high-performance desktops will now be visited on their low-end systems as well. "The Timna raises the bar as far as what it would take to have alternative technologies from RDRAM," another engineer said. "If Intel's value-end PC only supports RDRAM next year, that makes it awfully hard to fight."

Despite the board-design issues, "It makes sense for the Timna to use RDRAM," said Dean McCarron, principal of market watcher Mercury Research (Scottsdale, Ariz.). Using integrated RDRAM in the low-cost PC can lower overall memory costs, since it takes less memory to deliver adequate performance.

"One of the reasons Intel went with RDRAM is that the memory controller is only 30 pins per channel," said one major Taiwanese motherboard manufacturer. "That's much easier to move onto the CPU silicon than the standard SDRAM memory controller."

Another advantage is that you can increase bandwidth with a fairly low rise in pin count. "With one channel at 30 pins, you get 1.6 Gbytes of bandwidth," said an engineer for another Taiwanese motherboard maker. "With 60 pins you get 3.2 Gbytes and with 90 pins you get 5.4 Gbytes, and so on."

While Intel's schedule calls for rolling out Timna in the third quarter of next year, McCarron said it could take an additional six months for value-segment PC makers to begin the switch from SDRAMs to Direct Rambus. Intel may have to delay Timna to early 2001, he said.

"Ultimately, RDRAM will migrate down to this level of the market," McCarron added. "Intel's designing Rambus controllers into Timna shows their assumption that RDRAM prices will migrate downward as well."

As they watch Intel reveal portions of its road map, motherboard makers are struggling to get their first PCs with Direct Rambus out the door. The second iteration of the Camino chip set (the 820 B0)  Intel's first core logic to support Rambus  is due to begin sampling here at the end of May.

Taiwanese motherboard makers are having somewhat mixed results with the development of RDRAM boards. The currently high price of RDRAM is a main stumbling block, but some motherboard makers are also having problems getting their RDRAM boards to run.

"The current [A1 version of] Camino has problems," said one Taiwanese engineer. "Now, it's hard for us to say if it's a core-logic problem, a Rambus memory problem or our board design. Hopefully the next iteration of Camino will work when we get it at the end of May. It usually takes a couple of revisions to get a working motherboard. RDRAM boards may take up to four revisions, though."

Another problem with the Rambus transition is the high cost of logic-analyzer equipment Rambus requires. In late April, Hewlett-Packard Co. staged demos here of its HP16700A and HP16702A logic analyzers geared to address testing issues with Rambus. The systems cost about $230,000.

"The cost is just too high for our company," said one R&D engineer. "We currently aren't using a logic analyzer for our RDRAM boards."

"We will let Intel solve the logic-flow problems," another engineer said. "We will concentrate on EMI and signal-quality issues of the board. For those problems, we have purchased a high-speed oscilloscope.

"The cost of the RDRAM memory is 50 percent higher than SDRAM," he went on. "When they have 128-Mbit parts, the cost premium will come down to 30 to 40 percent."

Mark Ellsberry, vice president of marketing for Hyundai Electronics America, said Timna will help drive RDRAM further down the ladder and into the value-PC segment. "I think Intel is very interested in getting Rambus into as many systems as possible," he said. "Over the next few years, we will see a gradual change in virtually all PCs, and SDRAM is going to be replaced by RDRAM. PC133 will stay in low-end systems for the next one to two years but will be forced out toward the end of 2000, when the price premium for Rambus memory starts to shrink."

Meanwhile, it is not yet clear where Intel is sourcing the graphics controller for Timna or exactly what is new about the Socket 370-S, which will first appear with the processor next year. "It's up in the air which graphics core they will use," said analyst McCarron.

Intel recently launched the 752 graphics controller, which McCarron described as a minor debug of its i740. "I would imagine the graphics core [for Timna] will be something completely different," he said.

Time is on Intel's side. Between now and the time Timna rolls, it could launch two generations of graphics chips from its Chips and Technologies unit or even strike a new partnership, McCarron said.

RDRAM operates in a highly serial mode, which works well with burst access but not so well with random access. This is different from much of the current graphics technology, so interfacing any existing graphics core with Rambus would require significant work, he added.

Glaskowsky said the core may use the same technology as Intel's upcoming Capitola graphics device, another update of the i740 due out later this year. Given the lengthy validation process for a complex chip like Timna, he said the company will need to freeze the design at least a year before the ship date and so has probably already decided on a graphics strategy.

"The best the Timna could be is a next-generation Celeron core with Capitola graphics," he said. "I give it a less than 50 percent chance that it will ever be released."